It is the ratio between the radius of cation to radius of anion.
Radius Ratio = rc/ ra
Depending on this we can say the shape of the 1:1 type ionic compounds and also the coordination number.
|
Sl. No |
Co-ordination Number | Radius Ratio |
Shape |
|
1 |
2 | > 0.155 |  |
|
2 |
3 |
0.155 to 0.225 |
 |
|
3 |
4 | 0.225 to 0.414 |  |
|
4 |
4 |
0.414 to 0.732 |
 |
|
5 |
6 |
0.414 to 0.732 |
 |
|
6 |
8 |
0.732 to 1.000 |
 |